DE4413490 shows such an instrument of the cylindrical vaginal applicator type, where irradiation positions are realized by a central catheter which is introduced into the applicator. The applicator can be connected to a so-called remote afterloading machine which via tubes moves a radioactive source to an irradiation position in the central catheter. In this device some radiation shielding is provided by a central filler element which is inserted in the applicator and can be made from different materials to provide differential radiation shielding with a relatively limited control over the dose distribution.
Such an applicator may comprise multiple catheters provided along a wall part of the cylinder, which thereby generally follows the form of the body cavity wherein the applicator is inserted. The guidance of the catheters along the wall part enables the irradiation doses to be shaped and so optimised, whilst keeping the dose at the surface of the organ at or below the desired limit. The irradiation is done by bringing a radiation source provided at the end of a guide cable via a transfer tube and the catheter to a predetermined correct position and allowing it to deliver radiation there for a predetermined length of time to combat the tumour.
It is noted that conventional applicators are instruments assembled from complex parts and frequently comprise long guide through bores that are difficult to clean when sterilizing the instruments for repeated use.
It is an object of the invention to provide an instrument which can be assembled quickly and introduced easily into the body cavity and whose positioning is accurate and reliable. In addition, it is an object to provide an instrument that is easily dis-assembled and so can easily be cleaned and sterilized.